Underwater geophysical prospecting



June 16, 1959 c. v. cooK UNDERWATER GEOPHYSICAL PBOSPECTING 2Sheets-Sheet 1 Filed Dec. 31, 1954 WIRES TO CHARGE FIG.

IN VEN TOR.

GO-DEVlL ROD c .v. coon A TTORNEVS June 16, 1959 c. v. COCK 2,890,861

\ UNDERWATER GEOPHYSICAL PROSPECTING FIGJO BY;- 69 2 A 7' TORNE V52,890,861 Patented June 16, 1959 fiice UNDERWATER GEOPHYSICALPROSPECTING Carl V. Cook, Bartlesville, kla., assignor to PhillipsPetroleum Company, a corporation of Delaware Application December 31,1954, Serial No. 479,186 2 Claims. (Cl. 255-61) This invention relatesto geophysical exploration under water. In one aspect it relates toapparatus for and a method of preparing cavities or holes under a bodyof water for receiving an explosive charge for geophysical exploration.In still another aspect it relates to a method for boring holes andplacing explosive charges below a body of water wherein a marker isallowed to remain which does not interfere with off-shore fishingoperations. In yet another aspect it relates to an improved knock-offbit, and adapter assembly for use in drilling in under water geophysicalexploration operations.

In prior art operations for off-shore geophysical exploration it is thepractice to drill a number of shot holes,

for example, from 40 to 50 holes, in advance of the shooting crew of menwho shoot the explosive charges in the holes. When holes are drilledwith or without placing of the explosive charges prior to operation ofthe shooting crew, it is necessary to leave markers in order that theshooting crew can locate the holes. Common practice has been in the pastto leave drill tubing in the hole and extending above the surface of thewater. This practice has been suspended in some states in which olfshoreregions are prospected because of state rulings requiring that suchoperations not interfere with fishing. It is obvious that drill holetubing which extends above the surface of the water or above the groundlevel and below the surface of the water could interfere with operationof fishing nets. To overcome this difiiculty and to permit a largenumber of holes to be drilled in advance of j the explosive charge andremoval of the drill tubing.

. One object of my invention is to provide a method for making a drillhole for placing an explosive charge whereinthe drill tubing is removed.

Another object of my invention is to provide a method for makingdrillholes for placing of explosive charges wherein the drill tubing isremoved and yet a marker is left.

Still another object of my invention is to provide an i improvedknock-01f and expendible drill bit, and adapter 7 assemblyfor use insuch operations.

Yet another object of my invention isto provide an improved drill bit,and adapter for use in said operations wherein the drill bit iseasilyseparated from the adapter and tubing and the latter are recovered forreuse.

These and other objects and advantages of my inven: tion will berealized upon reading the following description, which taken with the.attached drawing, forms a part of specification.

In the drawing Figure is an elevational view of my 2 knock-off drillapparatus positioned in a drill hole heneath a body of water. Y

Figure 2 is an elevational view, partly in section, of the apparatus ofFigure 1 after placement of an explosive charge. I

Figure 3 is an elevational view of a. portion of my apparatus. 1

Figure 4 is an elevational view of another portion of my apparatus.

Figure 5 is an elevational view, partly in section, of still anotherportion of my apparatus.

Figure 6 is an elevational view of still another portion of myapparatus.

Figure 7 is an elevational view, partly in section, of a portion of theapparatus of Figures 1 and 2 on an enlarged scale.

Figure 8 is a side elevational view, partly in section, of the apparatusof Figure 7.

Figure 9 is a plan view of a portion of the apparatus of Figures 7 and8.

Figure 10 illustrates an alternate form of a portion of my invention. a

Referring now to the drawing, in Figures 7 and 8 reference numeral 11identifies a collar or adapter which is provided with internal threads35 for attaching to the lower end of a drill tubing 53 (Figs. 1 and 2).Such a drill tubing is identified by reference numeral 53 in Figures land 2. The upper portion of this adapter 11 is identified by referencenumeral 12 while the lower portion is identified by reference numeral13. This lower portion 13 of the adapter is intended to telescope overan upper portion of a shank 15 of a drill bit 14. At the bottom of thedrill bit are disposed a pair of oppositely directed cutting edges 16.The cutting edges 16 are so disposed on lower portion of the drill bitthat when the tubing 53 and bit 14 are rotated by drivehead 51a in aclockwise direction the cutting edges advance into the earth. Drivehead51a is powered by engine 5112 which is supported on barge 51c. In thelower portion of the drill bit 14 and near the cutting edges 16 areapair of open ings 34 so disposed that drilling fluid can be pumpeddownward through the drill tubing and drill bit and through the holes tocool the cutting edges and to assist in carrying away the cuttings.These openings 34 are so positioned that th'e'discharge of thedrilling'fluid is on the back side of the cutting edges.

The drill bit 14 is provided with a shoulder 27 extending all the wayaround the bit. This shoulder serves as a seat for the lower end 28 ofthe adapterll. In order that the drill tubing which is threaded to theadapter can rotate the drill bit a plurality of keys or splines 26 areprovided on the outer periphery of the upper portion 15 of the bit.These keys or splines are disposed with their longitudinal axesvertical. A plurality of keyways 25 are provided in the inner surface ofthe lower portion 13 of the adapter in such a mannerthat the keys orsplines 26 match with the keyways 25. When the lower portion 13 of theadapter is positioned over the upper portion 15 of the drill bit withthe keys and keyways matching the drill bit is rotated upon rotation ofthe adapter.

Inorder to prevent the drill bit 14 from becoming dis engaged from theadapter 11 as the drilling assembly is lowered from the drilling rigthrough the water to the surface of the ground beneath the water one ormore shear pins 29 are provided. Holes are drilled at an angle of about30 from the horizontal in the wall of the lower portion 13 of theadapter. Horizontal holes are drilled through the shank portion 15 ofthe drill bit in such a manner that the holes in the adapter match theholes in valve least two shear pins can be inserted through theseopenings to hold the drill bit to the adapter until such time-itgisqdesiredsto separate Lthese members. .In some cases it ispreferable to provide four setssof' theseshearxpin '-holes*so.thatfour-'shear pins'can be used. I have found, thowever rthat in-gmost,applicationssthe useof two shear pins for holding the drill bit to theadapter are sufficient. 1 v As shear pins: I use ordinary-nails or sheetmetal nails. When using sheet metal nails or any other type of nail, iitispreferable that-the headsoflthe nails be made of lead so that uponinsertion of the nails through the. holes the heads. canbeflattenedagainst the outer surface of the adapter. In thismannerthenail-.heads 'will. not be sheared oif nor abraded duringthe drillingoperations. I prefer to construct the shearpin holes in the directions.d-isclosed above 7 so that upon driving a nail through .these-.openings. the. nailwill become bent and therefore will be held tightlyin place.

Asmentioned hereinbefore one. preferred method of operation of such adrill bit.is to use a-inud .or:merely :water as adrilling-fluid;Whenusingagdrillingfluid in this operation the fluid is pumped downward.through the drill tubing into the drill-bit and outvopenings 34 to coolthe cutting edges of the bit and to assist in removal of the cuttings.In order topreventcuttings or sands or other solid matter from flowingthrough openings 34 from the .bore hole into the drill: bit at suchtimes that drilling operations are suspended I-providea check valve 17.This. check valve permitsdownward flowof fluid through the tubing butchecks upward flow. In one embodiment this check valve'comprises a ringor plate 19 having an opening .31.centrally positioned therein.Immediately below. this plate is thevalve 21 of the assembly. In one.embodiment I preferto use leather as the valve. This valveis'circularin shapenand has a diameter about the .same as the outside diameter ofthe drill shank 15. This .valve has a. support ring 21a which rests uponan upper surface 24 of the shank, see Figure 7. A flapper 21b is movablyattached, by neck 210 to support ring 21a. The flapper, neck. and ringare. usually made from one piece of material, as leather, by merelycutting out a section leaving slot 21d. .An opening 30 (Figs. 7 and 8)in the valve 17 is 'for passageof fluid downward when the .valve isopen. Washers.20 and 22'are provided on .the upper and lower faces.respectivelyv of .valve 21. The diameter ofthe larger washerzz and thediameter of the opening.31 in plate 19 are related in such amanner thatwhen upward pressure against the valve is greater than downward pressurethereon-the valve closes and the flapper 21b cannot be forcedupwandthrough opening 31. A bolt 23 extends through washers 20and 22 andthrough the valve 21 to hold these three members together. A shoulder orflange Y 18 is provided around the inner periphery ofthe adapter 11 at alevel intermediate the threaded section and valve 17 to prevent thevalve assembly from moving upward. It is not necessarythat shoulder .18.hold the valve assembly tightly against shoulder 24 but the valveshould be maintained in close :proxirgrity to the shoulder 24 asillustrated in Figures 7 and v In Figure 8 thevalve- 17 is illustratedas beingin an open position while Figure 7 shows the valve closed.

Figure-9 is a plan'view illustrating valve 21. The valve comprises aring 21a, a flapper 21b, neck 21c with a slot 21d permitting freemovement of flapper 21b.

Figure is' a sectional view of a portion of a shank a ofa' drill bitsimilar to bit 14 of Figures 7 and 8, provided with a keyway 25a, and aportion of a collar or adapter 11a with a key or spline 26a matching thekeyway 25a. e I f Inthe operation and use "of the apparatus of myinvention; the drill .bit 14 is attached to the adapter. 11 with ne'iormore shear pins .29 af ter positioning the'check 17. The adapter 11 isthen threaded onto the lower end of the drill tubing and the bit anddrill. tubing are then lowered through the water preparatory todrilling. Any suitable above water drilling means can be used, such asdrilling apparatus on a floating barge or on a more or less conventionalboat. About the only require ments being that the power apparatus beadaptable for rotating the drill tubing and :bit and furthermore thatthe power apparatus, be maintained relatively still so as not to bendthe tubing by horizontal movement of the barge or boat. After thedrilling is started water is usually pumped into the top. of thedrilltubing and, is forced through the check valve 17 and throughopenings 34 and this water with drill cuttings flows upward around thedrill bit and adapter and out the top of the drill hole. Such operationis continued until the hole has been drilled to a desired depth. Thedrilling is then stopped and a go-devil 60 (Figure 6) is dropped downthe tubing and upon impact against the check valve 17 shears'the shearpins29 to free the drill- 14.from-the adapter 11.; The drill bit 14is'in some instances raised, upwardand away from the bottomof the drillhole and the go-devil is then dropped thereby shearing pins 29 andloosening the drill bit 14 from the collar or adapter 11. The plate 19is usuallymade ,sufliciently thick that it can withstand the impact ofthe go-devil. This go-devil.60.is substantially a piece of iron 2% to3.inches in diameter and from 3 to 4 feet in length and is ofconsiderable weight. The godevil should be sufficiently heavy, that whenit is dropped down thetubing it will strike the upper portion of thevalve. or the upper surface 24. of the drill. bit with sufficientforceto shear the pinsvand loosen the bit. It is necessary; to retrievethe go-devil notonly for further use insubsequent operations butIOuIIIlOVE it from the tubing for placing ofthe explosive charge. Inorder to retrieve the go-devil an eye bolt 61 or;hook is attached to thetop of the go-devilsand, cable is attached thereto in such a manner thatthe go-devil can be pulled up the tubing after it has served, itspurpose. vAfter the go-devil has been removed from the tubing and ofcourse the adapter 11 loosened from the drill bit, an explosive charge56 (Figure 2) is then lowered through the tubing 53. A pairof .wires 55are ,attachednto the charge for passage of electric current fordetonation. The wires are, of sufficient length to'extend from thecharge at the bottom of the borehole to a level well above the surfaceof the water 51. I use one of several methods for removing the drilltubing and adapter from the drill hole. One method involves attaching afloatsuch as a wooden float 59 (FiguresZ and 3) to the upper ends ofwires 55, and then the tubing is pulled upward and over the float. Asthe lower end of the tubing 53 and the adapter. 11 are removed from thewater the wooden float 59 floats on the water. This woodenfloat is thenallowed to remain as a buoy or float to identify the locationof the borehole withits explosive charge. The actual drill bit 14 is the only pieceof apparatus which is notretrieved for further use. Sincethese drillbits are inexpensive their loss is a very small item. v

Another means for wi drawing the tubing 53 from the drill hole involvesuse of a hollow pipe .57 (Figure 4 closed, water-tight at both ends. Useof thishollow pipe in retrieving the drill tubing is similar to thatdisclosed relative to the wooden float 59. Ahook .or eyeSS isprovided atone end of pole 57 for attachment of the upper ends of wires 55. ,1

Reference numeral 52 identified the surface of the earth beneath thebody of water. 1

I use still another method for marking of the drill hole after placementof the explosive charge. This latter method involves use of a steel band54 bent generally into the form of a circle with theends being boltedtogether as illustrated in Figure 5. The circle so formed is tied to theupper endsof wires 55 after the explosive charge is placed and is forcedinto the top of the tubing 53. Upon removal "of the tubing 53 upward the'band 54 slides through the tubing and as the lower end of the tubing 53approaches the water level the band 54, is caught with a hook toretrieve the ends of the wires 55. After the band 54 is removed from thetubing the wires are disconnected from the band and a float such as thehollow pole 57 or wooden float 59 is attached to the wires for permanentmarking.

As many drill holes as desired can be produced in a manner hereindisclosed with each drill hole being marked by a float. When using suchfloats as float 57 or float 59 fishing nets are easily operated andthere is no danger whatever of obstructing movement of the nets. As soonas the net passes over a given float the float will merely rise to thesurface of the water again.

I prefer to use a 4 inch drill tubing so that an. explosive chargepackage having a relatively large diameter can be used. When using anexplosive charge of relative large diameter the entire charge isconcentrated more nearly at a point. A charge so shaped is moreefficient for geophysical exploration than is a long charge of smalldiameter such as would have to be used if the drill tubing were smallerthan 4 inch tubing.

By increasing the length of tubing 53 the drill hole can be drilled toany desired depth under water. In general the deeper the drill hole ismade the smaller the explosive charge can be and yet carry out eflicientgeophysical exploration.

While I have described the shear pin holes in the lower portion 13 ofthe adapter 11 as being drilled at an angle of about 30 from thehorizontal this angle is not critical and it can be sloping at anglesmore or less than 30 as desired, but the hole should be sloping to asufiicient degree that a nail driven therethrough through and through acorresponding horizontal opening in the drill shank will be bent andtherefore held rigidly in place.

From the above description it is seen that an improved knock-off bit,and adapter assembly have been devised which permit drilling of, forexample, a hole With a 4-inch diameter drill tubing for use ofconcentrated explosive charges. Furthermore the drill bit is rigidlyheld by a plurality of keyways and shear pins to a collar or adapter onthe lower end of the drill tubing. My invention provides an improvedmeans of planting explosive charges under the floor of bodies of waterwithout requiring that the drill pipe be left in place between the timethat the drill hole is made and explosive charge is set off. Even whendrill pipes are allowed to remain in the holes after placing the chargesthey are removed after the charges are detonated and all observationsare terminated. The invention further illustrates methods for gettingthe wires to the charge through the drill pipe to permit removal of thepipe without interfering with the wires. Other diameter drills and drillpipes can be used when desired. The 4-inch drill and tubing weredescribed merely as a preferred example when drilling holes forexplosive charges in geophysical exploration operations.

One alteration suitable for use with the apparatus of my invention isthat a key can be made integral with the inner surface of the lowerportion 13 of the collar or adapter 11 and the matching keyway formed inthe outer surface of the drill shank 15 in place of the key on the drillshank and keyway in the collar as described hereinbefore.

While certain embodiments of the invention have been described forillustrative purposes the invention obviously is not limited thereto.

I claim:

1. Apparatus for preparing a cavity for an explosive charge in the earthbelow a body of water comprising, in combination, a drill bit adaptedupon rotation to bore a hole into the earth, a drill tubing for rotatingsaid bit, means for rotating said tubing, means for transmittingrotation from said tubing to said drill bit comprising a collar on thelower end of said tubing, the lower portion of said collar surroundingthe upper portion of said drill bit, at least one key disposed axiallyon one of the outer periphery of said upper portion of said drill bitand the inner periphery of said lower portion of said collar, and amatching keyway on one of the inner periphery of said lower portion ofsaid collar and of the outer periphery of said upper portion of saiddrill bit respectively, and means for holding said upper portion of saidbit Within said lower portion of said collar, this latter meanscomprising at least one shear pin extending through the walls of saidupper portion of said bit and the lower portion of said collar, a checkvalve assembly supported by the up per end of said upper portion of thedrill bit, a flange on the inner surface of said collar above andadjacent said check valve assembly holding same against upward movementand the valve of said assembly being positioned to open in a downwarddirection for downward circulation of fluid through said tubing, bit andcheck valve assembly.

2. A knock-off bit and adapter assembly comprising, in combination, anadapter of circular cross section, means to attach the upper portion ofsaid adapter to a drill tubing, a drill bit adapted upon rotation tobore a hole into the earth, the upper portion of said drill bit beingdisposed within the lower portion of said adapter, at least one keydisposed axially on one of the outer periphery of said upper portion ofsaid drill bit and the inner periphery of said lower portion of saidadapter, and a matching keyway on one of the inner periphery of saidlower portion of said adapter and of the outer periphery of said upperportion of said drill bit respectively, means for holding said upperportion of said bit within said lower portion of said adapter, saidlatter means comprising at least one shear pin extending through thewalls of said upper portion of said bit and the lower portion of saidadapter, a flange disposed around the inner Wall of said adapterintermediate its upper portion and its lower portion, and a check valveassembly supported by the upper portion of said drill bit and heldagainst. upward longi tudinal movement by said flange, and the checkvalve of said assembly being positioned to open in a downward directionfor downward circulation of fluid.

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